Effects of Temperature on the Rate of Formation and Density of Polyurethane Foam
Alex, Colin
Introduction
The polyurethane foam consists of mixtures Part A (poly ether polyol, tertiary amine, trichlorofluoromethane, silicone surfacant) and Part B (polyfunctional isocyanates). The foam is formed by creating a polyurethane polymer with the fluorocarbon blowing agent. A blowing agent helps to form foam, and makes it more stable. The polymer is formed in a reaction of the polyester polyol and a polyfunctional isocyanate. The amine is used as a catalyst. The surfacant is used to modify the characteristics of the polymer when it is being formed.
The first work on polyurethane polymers was done by Otto Bayer and his coworkers in the I.G. Farben laboratory in Germany in 1937. Polyurethane foams can be made with different densities and rigidity for different uses. It is used in construction to furniture to shoes, and has many other uses as well.
The purpose of this experiment is to test the effects of temperature on how fast the foam forms, and the effects on the volume of the foam.
Procedure
We used two 50mL beakers to heat/cool the mixtures in, and mixed them together in a plastic cup. We used 20mL of each mixture, and a new plastic cup for each mixture. First, we mixed the two together at room temperature in the plastic cup, stirred, and recorded the time it took to foam to the top of the plastic cup. We then poured 20mL of A in one beaker, 20mL of B in the other beaker, and heated them on a hot plate to 45°C. Once the mixtures reached the temperature, we poured them in the plastic cup, stirred and recorded the time. We then poured 20mL of A in one beaker, 20mL of B in the other beaker, and placed them in a cold water bath, and cooled them to 10°C. We poured them in a plastic cup, stirred and recorded the time.
We allowed them to harden, and filled a 2L beaker to 1200mL, in order to find the volume of the foam. We placed a foam in the water, recorded the volume, and repeated for the other 2 foams.
Results
Temperature (°C)
Time to Reach Lip of Cup
Volume (mL)
10
2 minutes 33 seconds
600
22 (room)
1 minute 37 seconds
600
45
23 seconds
600
The temperature affected the shape of the foam and the size of the bubbles. The coldest foam had the smallest bubbles and held a mushroom shape. The room temperature foam had a similar shape, but had larger bubbles. The hottest foam had the biggest bubbles, and did not hold a shape - it just spilled down the sides of the cup.
From left to right: 10°, 22°, 45°
Conclusions
The higher the temperature the shorter amount of time it took the two chemicals to react. The lower the temperature the longer it took for the two chemicals to react. So yes temperature does affect the time of the reaction. Both of the substances that we used sticked to the bottom of the beakers so we weren't able to obtain exactly 20 ml of each substance. Other researchers could add another substance to the mixture or change the altitude at which the experiment is done. We could improve the experiment by making the measurements and the temperatures more exact.
References
Polyurethane Foam
Chemical Demonstrations, Bassam Z. Shakhashiri, 1983, Polyurethane Foam, p. 216-218
Effects of Temperature on the Rate of Formation and Density of Polyurethane Foam
Alex, Colin
Introduction
The polyurethane foam consists of mixtures Part A (poly ether polyol, tertiary amine, trichlorofluoromethane, silicone surfacant) and Part B (polyfunctional isocyanates). The foam is formed by creating a polyurethane polymer with the fluorocarbon blowing agent. A blowing agent helps to form foam, and makes it more stable. The polymer is formed in a reaction of the polyester polyol and a polyfunctional isocyanate. The amine is used as a catalyst. The surfacant is used to modify the characteristics of the polymer when it is being formed.
The first work on polyurethane polymers was done by Otto Bayer and his coworkers in the I.G. Farben laboratory in Germany in 1937. Polyurethane foams can be made with different densities and rigidity for different uses. It is used in construction to furniture to shoes, and has many other uses as well.
The purpose of this experiment is to test the effects of temperature on how fast the foam forms, and the effects on the volume of the foam.
Procedure
We used two 50mL beakers to heat/cool the mixtures in, and mixed them together in a plastic cup. We used 20mL of each mixture, and a new plastic cup for each mixture. First, we mixed the two together at room temperature in the plastic cup, stirred, and recorded the time it took to foam to the top of the plastic cup. We then poured 20mL of A in one beaker, 20mL of B in the other beaker, and heated them on a hot plate to 45°C. Once the mixtures reached the temperature, we poured them in the plastic cup, stirred and recorded the time. We then poured 20mL of A in one beaker, 20mL of B in the other beaker, and placed them in a cold water bath, and cooled them to 10°C. We poured them in a plastic cup, stirred and recorded the time.
We allowed them to harden, and filled a 2L beaker to 1200mL, in order to find the volume of the foam. We placed a foam in the water, recorded the volume, and repeated for the other 2 foams.
Results
The temperature affected the shape of the foam and the size of the bubbles. The coldest foam had the smallest bubbles and held a mushroom shape. The room temperature foam had a similar shape, but had larger bubbles. The hottest foam had the biggest bubbles, and did not hold a shape - it just spilled down the sides of the cup.
Conclusions
The higher the temperature the shorter amount of time it took the two chemicals to react. The lower the temperature the longer it took for the two chemicals to react. So yes temperature does affect the time of the reaction. Both of the substances that we used sticked to the bottom of the beakers so we weren't able to obtain exactly 20 ml of each substance. Other researchers could add another substance to the mixture or change the altitude at which the experiment is done. We could improve the experiment by making the measurements and the temperatures more exact.References
Polyurethane FoamChemical Demonstrations, Bassam Z. Shakhashiri, 1983, Polyurethane Foam, p. 216-218